Exhaust manifold systems of internal combustion engines are subjected to extremely high and variable temperatures during operation causing expansion and contraction of the manifold components. It has been the practice, particularly on large engines, to make the manifolds in multiple sections and to interconnect the sections by sliding couplings and/or flexible bellows, thus reducing the possibility of damage which results from expansion and contraction. Sliding couplings without seals have a tendency to allow exhaust gas leakage. Flexible bellows provide a positive seal and compensate for expansion, but the known methods employed to sealably connect the flexible bellows in place are too difficult to service.
Representative of the art in this area is U.S. Pat. No. 3,490,794, issued Jan. 20, 1970, to M. A. Swanson, which teaches an exhaust manifold joint including a protective tubing slidably fitted within the ends of the manifold sections, and a flexible bellows member removably secured to the manifold sections by annular clamps. The tubing prevents the hot exhaust gasses from acting directly on the flexible bellows, guides the exhaust gasses through the manifold system and axially aligns the sections. Since the tubing is slidably fitted within the ends of the manifold sections, the intermediate sections of the manifold cannot be removed for servicing the related cylinder head without first starting at an end section and serially disconnecting the manifold sections. This is time consuming and expensive especially on large engines where each manifold section may weigh 27.24 kilograms (60 lbs.) or more.
U.S. Pat. No. 3,820,829, issued Jun. 28, 1974, to Hasselbacher et al., likewise teaches a liner arranged between the tubular sections and an interconnecting flexible bellows secured by solid locking rings of resilient material at each end thereof. For the most part, these couplings are too difficult to manufacture, assemble, or disassemble.
In some applications, a separate rigid joint is spaced away from the flexible coupling to allow disassembly of the individual manifold sections. This is undesirable because it introduces additional complexity to the manifold casting resulting in increased cost and additional sealing problems.
In certain sections of the manifold pressure waves react on the internal surfaces and cause a pulsing action. If not properly supported, this pulsating action causes the manifold section to vibrate and the attached flexible bellows to continually flex which results in premature metal fatigue.
Therefore, what is desirable is an improved flexible assembly for an exhaust manifold system having an economical flexible coupling device between individual manifold sections that is simple and of rugged construction. Moreover, the flexible coupling device must be sufficiently flexible to accept expansion and contraction within the manifold system while preventing the leakage of the exhaust gas between the individual sections. It is also desirable that the flexible coupling device provide axial alignment and support between the individual sections preventing vibration while permitting an individual manifold section to be removable from its respective cylinder head for service without the need to disassemble adjacent manifold sections. It is also desirable that the hot exhaust gasses pass smoothly through the manifold sections with a minimum amount of turbulence, and that the annular flexible bellows be protected and not be in direct contact with the flowing hot gasses which can drastically effect the service life of the flexible bellows.
The present invention is directed to overcoming one or more of the problems set forth above.